It is known to provide a control valve to control the throughflow of a liquid, for example, in a hydraulic damping unit which can have a hydraulic damping unit which can have a hydraulic piston-and-cylinder arrangement, whereby between an inlet and an outlet, a throttle element is provided.
In the conventional device of this type, a pipe or tube is provided in which a flow body is received and upon which a pressurizable bellows is provided to control the throughflow by varying the flow cross section. An automatic control of the throughflow as a function of the internal pressure is not, however, possible with this arrangement since the bellows responds to externally applied pressure.